There are almost 150 possible attributes available for Dot graphs, and
it can be difficult to know which ones to use. This module provides
helper functions for the most commonly used ones.

The complete list of all possible attributes can be found in
Data.GraphViz.Attributes.Complete; it is possible to use both of
these modules if you require specific extra attributes that are not
provided here.

A convenience class to make it easier to create labels. It is
highly recommended that you make any other types that you wish to
create labels from an instance of this class, preferably via the
String or Text instances.

Colors

The recommended way of dealing with colors in Dot graphs is to use the
named X11Colors rather than explicitly specifying RGB, RGBA or HSV
colors.

These functions also allow you to use SVG and Brewer colors, but
X11 colors are generally preferable. If you wish to use SVG
colors, either import this module hiding X11Color or import the
SVG module qualified.

The X11 colors that Graphviz uses. Note that these are slightly
different from the "normal" X11 colors used (e.g. the inclusion
of Crimson). Graphviz's list of colors also duplicated almost
all Gray colors with Grey ones; parsing of an X11Color
which is specified using "grey" will succeed, even for those
that don't have the duplicate spelling (e.g. DarkSlateGray1).

Specify the fill color of a node, cluster or arrowhead. Requires
stylefilled for nodes and clusters. For nodes and edges,
if this isn't set then the color value is used instead; for
clusters, bgColor is used.